Polyethylene-based nanocomposites for radiation shielding: modelling in radiative environment and laboratory tests in thermo-vacuum chamber

Human space missions beyond near Earth orbit call for new materials to mitigate risk factors associated with radiation exposure. Current materials show many limitations in this regard for applications in crew exploration vehicles, spacesuits and human habitats. The technological solutions are mainly based polyethylene materials, which have high hydrogen content. These polymers are non-structural and their overall properties are quite low, considering the operative conditions in space. The use of nanoparticles, in particular the carbon-based ones, is a promising approach to improve the overall properties of polyethylene materials. In the first part of this work, we performed an extensive study modelling the radiation shielding behaviour of nanocomposites with polyethylene matrix using the code HZETRN by NASA. Polyethylene modified with different types of nanoparticles at several weight percentages were modelled to evaluate the radiation shielding effectiveness. The behaviour of polyethylene-based nanocomposites were compared with those of a number of materials typically used in space. Simulations involved different radiative environments, such as GCR, SPE and LEO. Results are presented for the latter scenario. In the second part of the work, we performed experiments on selected polyethylene-based nanocomposite materials. In particular, we carried out tests in simulated space environment using a thermo-vacuum chamber and a Sun simulator to investigate the effects of the nanofillers on the thermoplastic matrix.